Current applications in the field of seismic monitoring and imaging use modular and discrete sensor “sondes” interconnected by cable or ridged pipe containing analog or telemetry conductors. These sensor arrays must typically be deployed in protected wellbores, and often experience failures in interconnections, fluid intrusions, and other mechanical disruptions. The complexity, unreliability, and cost of these conventional systems often precludes commercially-viable permanent, semi-permanent, or long-term applications of the technology.
Coiled tubing, widely used in the oil and gas industry, is typically used in oilfield intervention products for delivering fluids and flow conduits into wellbores. Such tubing is typically made of steel but may be made of other metals or composites depending on the chemical contents of the wells where it will be used. Coiled tubing can be rolled up onto a “spool” for transportation and then subsequently “injected” into an oil well.
Individual sensing devices have been deployed in coiled tubing with a wireline or other communication channel internal to the coiled tubing, with the sensors recording information as they move up and down the well. However, this arrangement does not allow for mapping the subsurface beyond the immediate area around the wellbore.
Coiled tubing has been used with sonde-based sensors for seismic surveys, but has not achieved popularity due to the difficulty and expense of getting an array of traditional wireline sensors into coiled tubing and back out again for servicing.
Thus, there is a need in the art for sensors suited to deployment in coiled tubing and wellbore environments that overcome the disadvantages of conventional approaches identified above.